Springs and Bearings Flashcards
(17 cards)
What are the purposes of a spring?
Property of elasticity, absorb energy by distorting or deflecting when under load, store it in their loaded state, then release it in a controlled manner as they return to their original shape after the load has moderated.
What did early springs consist of?
They consisted of flat and curved sections of wood (and later metal), used in the suspension of carts and carriages.
What types of springs are there?
Helical compression spring Helical tension spring Helical torsion spring Torsion spring rod (torque tubes) Coned disc (Belleville) spring Flat spiral torsion spring Liquid spring Pneumatic spring Elastomeric (rubber)spring Leaf spring
Helical compression spring
Open helical spring which resists a compressive force.
made in various forms and from different shapes of wire depending on use.
Same diameter for its entire length and is known as a straight spring.
Load, deflection and maximum solid length need to be known.
Typical aircraft applications
Piston engine (valve springs in cylinder heads)
Damping rods/pogo rods in various systems(flight controls)
Shock strut dampers on smaller aircrafts
Reference springs in various controls
Control valves
Helical tension springs
Close wound which resists a tension force applied to the ends of the springs, through suitable end forms, simple hooks and loops.
Tension spring is available in may varieties of end geometry (eye, hook, screw, etc)
Typical aircraft applications
Analogue instruments/indicators Flight controls system Wire tensions regulators Down lock springs on retractable landing gear systems Up lock hooks on landing gear doors
Spring rod
Try to avoid the use of tension springs where possible especially in safety critical situations. this is because tension springs are more likely to suffer fatigue and fracture than is a compression spring.
these are used where both tensile and compressive force is required.
it contains a compression spring but may operate to simulate a tension spring.
Helical torsion spring
Store energy or offer resistance to an applied torque when subjected to an angular deflection. this results in an increase in the number of coils in the spring and a relative decrease in the springs diameter.
subject to bending stresses
Flat spiral springs
flat material wound on itself with open space between the coils in the free position.
these are made to deliver a torque, uses linkages for linear action
widely used for clocks gauges indicators, locks and for maintaining pressure on carbon brushes on electric motors and generators.
Torsion spring rods
tubular rod, elastic properties, attains spring like properties when exposes to torsional loadings.
Member in vehicle suspension.
Typical aircraft applications
flight control system
Coned disc springs
Belleville springs can be used in a number of applications. used in compression whenever space is limited. can be stacked in parallel or series.
Leaf and flat springs
vehicle suspension, it absorbs and transforms energy generated when the aircraft lands, a flat spring is like a leaf spring but has only one flexible component.
Pneumatic springs (oleo)
Gas dampeners. used to dampen out dynamic motion in mechanical systems, converts mechanical movement first into pressure, which is then converted into heat energy.
Liquid springs
Principally incompressible. only be able to dampen dynamic motion by converting pressure into heat. sometimes used as shock absorbers on high speed aircraft landing gear systems
Elastomeric springs/dampeners
elastic properties, dampen movement of rotor blades at their joining.
also be used as dampening materials between metal roller or ball bearings.
supports very long driveshaft.
